Modelling Advanced Air Suspension with Electronic Level Control in ADAMS/Car

Sammanfattning: Multi-body simulations are given more emphasis over physical tests owing toenvironmental, financial, and time requirements in the competitive automotive industry. Thus,it is imperative to develop models to accurately predict and analyse the system's behaviour.This thesis focuses on developing an air suspension model with Electronic Level Control thathas the ability to communicate with other air springs in a pneumatic circuit thus replicating thepneumatic connection in actual truck and regulate the ride height of the vehicle.To accomplish this, a comprehensive literature study is performed to identify an effectivecontrol variable to manipulate the air springs. This is done by understanding the working andthermodynamic principles of air suspension, understanding various Scania pneumaticconfigurations, and decrypting the working of the Electronic Level Control.Different methods for implementing the model through the identified control variable arediscussed. A brief explanation of the necessary physical tests performed to validate the modelis given. An extensive description of implementation of the static and dynamic model inADAMS through command batch script coding is provided.The developed static model is validated by comparing the results from simulations and the testdata. The axle weights have an error of maximum 6% and the pressure in the air springs havean error of maximum 9% which can be owed to neglection of hysteresis in the air springcharacteristics and using mean values to compare the data. The dynamic model is validated byaltering the ride height level and observing the response of the model. The results obtainedindicate the developed Electronic Level Control is able to regulate the ride height at the desiredlevel.The robustness of the model is validated by modifying the developed model for longitudinalpneumatic connection and for a truck with trailer model. The results indicate the developedmodel is capable to perform satisfactorily and conform to the Scania tolerance limits.Thus, an appropriate control variable for the air springs model is identified. Static and dynamicmodel to identify the suitable pressure in the air springs and thus, the force in the air springs isdeveloped which helped in drastically reducing the manual iterative work that was required.